Rotary and input drilling apparatus



Aug. 25, 1964 R. w. BROWN ROTARY AND INPUT DRILLING APPARATUS R. W. BROWN FIG. 3

ROBINSON W. BROWN INVENTOR.

Aug. 25, 1964 R. w. BROWN ROTARY AND INPUT DRILLING APPARATUS 3 Sheets-Sheet 5 Filed DeG. 2l, 1961 ROBINSON W. BROWN INVENTOR.

ATTORNEY United States Patent O 3,145,787 ROTARY AND INPUT DRILLING APPARATUS Robinson W. Brown, San Antonio, Tex., assignor to Jersey Production Research Company, a corporation of Delaware Filed Dec. 21, 1961, Ser. No. 161,055 3 Claims. (Cl. 175-107) The present invention is broadly concerned with drilling boreholes into the earth and is more especially concerned with an improved impacting tool designed for use in drilling such boreholes. The tool is particularly characterized by a novel means for periodically and repeatedly combining a longitudinal vibratory drilling action with a torsional vibratory drilling action against a rock surface being drilled.

In present day practice, a large proportion of the boreholes drilled into the earth are drilled by the rotary method. In carrying out this method, a string of drill pipe provided with the bit at its lower end is first run into the borehole. The drill string is rotated from the surface to disintegrate the formation beneath the bit. The drill bits normally used in such operations include drag bits, roller cone bits and the like. These bits, or more specifically their cutting elements, depend primarily for their drilling action upon a scraping or grinding action as they are rotated on the bottom of the borehole. A drilling fluid is circulated down through the drill pipe and back through the annulus between the drill pipe and the wall of the borehole to remove the broken rock or cuttings and seal the wall of the hole.

A substantial portion of the expense incurred in rotary earth drilling is due to the low penetration rates obtained with conventional tools. This is especially true in hard abrasive formations, since the rotary system is characterized by rotation of the bit under static load. When hard abrasive formations are encountered, the bit may advance at the rate of a foot per hour or less. This slow rate is attributed to the inability of the bit to penetrate into or crush the formation immediately beneath the cutting elements; and thus only a scraping or grinding act-ion is utilized in disintegrating the formation. As a consequence, only small fragments of the formation are removed with each rotation of the bit. While it might appear from this that drilling in hard formations requires lower torques than soft formations, the converse is actually the case.

To alleviate the shortcomings of standard rotary drilling practices, especially in hard abrasive formations, percussive type drilling methods and tools have been developed. However, most of these tools operate to develop an axial percussive force with respect to the hole being drilled and deliver their impact energy solely in a longitudinal manner. Further, they are not able to adjust their drilling action to the type of formation being drilled.

Longitudinal or downward impacts crush a formation being drilled-and cause it to fail in compression. It has long been recognized, however, that the most effective penetrating force is achieved by imparting a combined torsional and longitudinal action to a drill bit, An action of this type results ina motion which serves to simultaneously. compress and shear the formation encountered lby the bit. In this connection, it is a principal object of this invention to provide a simple and effective drilling apparatus capable of applying combined longitudinal and torsional vibrations to a drill bit.

It is recognized by those skilled in the art that soft or readily drilled formations do not require impact forces to be drilled `in an economical manner. Merely rotating .the drill `bit with a compressive force on it effectively drills such formations. vIt is likewise recognized that in hard abrasive formations .percussive drilling becomes 3,145,787 Patented Aug. 25, 1964 more effective. In this respect, however, it is important to note that conventional percussive or impact type tools generally cannot adjust to different types of formations. That is, when a percussive tool is in operation it continues its percussive impacts regardless of the type of formation being drilled.

It is, accordingly, an object of the present invention to provide a drilling tool which is so designed that the drill bit rotates and drills in a conventional manner when easily drilled formations are encountered. Upon encountering a hard-to-drill formation, however, the tool operates as a percussive tool.

It is a further object of the present invention to provide an apparatus which is superior to existing apparatus and methods in its ability to drill effectively and eiiiciently through a variety of earth formations. Other objects and features of this invention will become more apparent from the following description and attached drawings in which:

FIGURE 1 is the longitudinal sectional view of the major components in the lowerportion of a drilling apparatus which embodies this invention and which is contemplated to constitute the best mode of carrying out the invention;

FIGURE 2 is a sectional view illustrating the major components in the upper portion of the drilling apparatus shownin FIGURE l;

FIGURE 3 is a section along lines A-A of FIG- URE l;

FIGURE 4 is a section along lines B-B of FIG- URE 1;

FIGURE 5 is a side elevation isometric of a part of FIGURE l in the general area of lines B-Bg and FIGURE 6 is a side elevation isometric of an upper part of FIGURE l.

Referring to FIGURE 1, the drilling tool includes a cutting element or drill bit 10 which acts to drill a borehole into the earth. This element, as shown, depicts what is conventionally designated as a star type drilling bit. However, this invention may be practiced with other types of drill bits, such as roller cone bits, drag bits and the like.

Element 16 is connected by threads to anvil or cylindrical sub 24 which in turn is connected to cylindrical case 22 by a bearing joint noted generally by legend 12. Joint 12 comprises a lower cylindrical sleeve 14 threadedly connected to a cylindrical spacer sleeve 416. Sleeve-16 in turn is threadedly connected to case 22. Fitting into the space created by parts `14, 16 and 22 are bearings l. Bearings 13 also fit into annular groove 20 provided in sub or anvil 24. The relative position of these parts is further clarified by referring to FIGURE 3 which is a cross section taken at A-A of FIGURE l. vBearing joint 12 permits bit 1i) and anvil 24 to have limited axial movement and free rotational movement with respect to cylindrical case 22.

Cylindrical case 22 is connected at its upper end by threaded joint 23 to a second cylindrical case 27, as shown in the lower part of FIGURE 2. Secondcase 27 is in turn connected by threaded joint 25 to conventional drill pipe 26 which extends to the earths surface and is conventionally connected to standard rotary oil well drilling surface equipment, not shown. Cases 22 and V27 may be considered as an outer case assembly.`

Referring to the lower part of FIGURE l, anvil 24 fits in case 22 and contains a recess 28 in which is placed a sealing element such as O-ring 30. The sealing element permits movement of anvil 24 with respect to case 22 and maintains a fluid tight seal of part of the lower end of an annular space created by case 22 and tubular shaft 32. Another O-ring or equivalent sealing element 34 in recess 36 on the inner bore of anvil 24 completes the lower seal of the annular space. Oil is placed in the annular space for lubricating moving inner elements of the drilling apparatus.

On the top of anvil 24 are clutch lugs 38. These lugs are adapted to engage corresponding clutch lugs 4t) on the lower end of slidable cylindrical shaped hammer member 42. Anvil 24 and hammer member 42 together comprise the rotary impacting and clutching element of this invention.

The members which make up the impacting part of this invention may be better understood by referring to FIG- URES 4 and 5. FIGURE 4 is a cross section view taken at B-B of FIGURE 1 showing the position of lugs 38 and 40 in their near clutching position whereby drill bit is rotated through anvil member 24 and hammer member 42 as will be described later.

FIGURE 5 is a side elevation isometric of a part of FIGURE l in the general area of lines B-B and particularly illustrates the shape of lugs 3S, which have Vertical contacting faces. Lugs 38 may have cam or sloping surfaces on their trailing edges. Lugs 4f) have a similar shape but could have cam surfaces on their leading edges.

Referring again to FIGURE l, resilient members illustrated as lower spring 44 and upper spring 46 are shown in upper portion thereof. The purpose of these resilient members is to hold the hammer clutch jaws or lugs 40 in engagement with anvil clutch lugs 38, and to absorb and impart energy. Spring 44 rests on shoulder 48 of recess within hammer member 42, and its upper end is confined against a thrust bearing Sti. Thrust bearing 5i) in turn is confined against shoulder 52 of enlarged section 54 of shaft 32.

The lower end of resilient member or spring 46 rests on plate 56 which is attached to the upper end of hammer 42, The upper end of spring 46 is confined against a thrust bearing 58 which rests against shoulder 60 formed by an extension 68 in the bore of outer case 22.

Although two resilient members or springs 44 and 46 are described as used in the preferred embodiment of this invention, either member can be used to the exclusion of the other without departing from the scope of the invention.

Having described the drilling and impacting apparatus, attention is directed to the upper part of FIGURE 1 and to FIGURE 6 for a description of the driving connection between hammer 42 and driving shaft 32.

On the side of shaft 32 inclined channels or races 62 are formed. Although a single such channel can suffice, several channels are preferred. The hammer member 42 is provided with adjacent inclined grooves or channels 64 which are so placed lthat they cooperate with the channels 62 formed in driving shaft 32.

Ball members 65 and 66 are placed in each circular conduit formed by channels 62 and 64. This arrangement serves, upon rotation of shaft 32, to disengage hammer element 42 from anvil member 24. Operation of the arrangement will be described later.

The remainding members of the apparatus are illustrated in FIGURE 2. The lower part of FIGURE 2 is a continuation of previously mentioned extension 68 and outer case 22. Resting on the upper part of extension 63 is a bearing assembly noted generally by numeral 70. This assembly serves to support and join together the upper and lower sections 32 and 32", respectively, of tubular shaft 32. Immediately above bearing assembly 70 and upon which its upper end is confined is extension 72 of case 27. Extension 72 forms a part of oil reservoir 74 from which oil is supplied through conduits 76 and then through conduits 8 in assembly 7i) to lubricate moving parts in the similar space formed by outer case 22 and drive shaft 32.

In the upper end of reservoir 74 is floating gland 80. This gland serves to prevent drilling fluid mixing with 4 the oil and to equalize pressure between the oil and drilling tiuid in the drilling system.

Immediately above gland 80 are fluid ports 82 in drive shaft 32, which allow entrance of drilling fluid into the bore of shaft 32. Above ports 82 is a spline connection 84 for connecting the upper end of shaft 32 to a prime mover 86. The prime mover 86 may be any suitable motor-in this example it is shown to be a conventional axial flow turbine-having a shaft 88 and supported by bearing assembly 90.

The apparatus above described is an improved rotary drilling tool. The operation of the above apparatus can be better understood by the following description.

The assembly of FIGURES 1 and 2 is shown as it would be positioned in a borehole and attached to the lower end of drill pipe 26 extending downwardly from the earths surface. In operation of the assembly, mud ows downwardly through the bore of drill pipe 26 through bearing section 99 and into the impeller section of turbine 86. The mud impinges on impeller blades and causes the turbine to rotate. The mud then flows through the fluid passageways or ports 82 into the hollow shaft 32 which is connected to the rotor of the axial ow turbine 86.

The mud continues down the bore of shaft 32 and is discharged through fluid ports 3 of bit 10 on to the bottom of the hole. The drilling uid thus discharged picks up cuttings and carries them back up the annulus between the drill pipe and borehole wall to the earths surface.

In operating the apparatus, the drilling tool is run to the bottom of the borehole and drilling fluid is circulated from the surface through the bore of the drill pipe to the tool. Rotation of the drill pipe is initiated. Weight or a downward force is applied to the drill bit from the drill pipe and the outer case assembly through shoulder of sleeve 14, which in a sense is a continuation of the drill pipe, and contacts shoulder 4 of anvil 24. At this time turbine S6 is rotating shaft 32. Shaft 32 in turn causes the drill bit to rotate through the rotating and lifting connection of balls 65 and 66, channels 62, and channels 64, which rotates hammer 42 so long as readily drillable formations are encountered. Under these circumstances lugs 40 on the lower end of hammer 42 are connected to lugs 38 on the upper end of anvil 24 and springs 44 and 46 urge a rigid Contact of lugs 4t) and 38. The swivel or bearing connection 12 permits rotation of bit 10 irrespective of rotation of the outer assembly or drill pipe.

When drill bit 10 contacts a hard to drill formation, or in other words when the torque of shaft 32 transferred through lugs 40 and 38 is insufficient to turn anvil 24 due to the resistance of the formation being drilled, the lugs will be disengaged. This disengagement results from the torque of shaft 32, which causes balls 65 and 66 to roll up channels 62 and 64. As balls 65 and 66 roll up the channels, hammer 42 is raised and springs 44 and 46 are compressed storing up energy which is subsequently expended upon anvil 24 by hammer 42. As soon as lugs 40 rise to the height of the tops of lugs 38 they will continue rotation to a point of complete disengagement and will over-travel with respect to anvil 24. The lugs are then free of each other and the springs tend to extend themselves.

Springs 44 and 46 as they extend exert both a rotational and downward force on hammer 32. The rotational force releases balls 65 and 66; and the downward force causes the balls to roll back down to the bottom of channels 62 and 64 before the lugs 38 and 40 re-engage so that the hammer 42 strikes anvil 24 with a high impact. When the impact is made the hammer is traveling downward and rotating.

Hammer 42 strikes anvil 24 with both a longitudinal and torsional impact causing bit 10 to penetrate into a formation as it is rotated. That is, the drill bit cutting element simultaneously exerts a compression and shearing force on the formation being drilled. The rotation of bit can be further accentuated by having a sloping leading face on lugs 40 strike a sloping trailing face of lugs 38.

What is claimed is:

1. An apparatus for drilling a borehole in the earth including a drill string and comprising an outer case assembly adapted to be attached at its upper end to said drill string, an anvil positioned in said outer case assembly, means for rotatably and slideably supporting said anvil to said outer case assembly, a drill bit connected to said anvil, a hammer positioned above said anvil, a clutch connecting said anvil to said hammer, a drive shaft positioned in said hammer, a prime mov'er connected on the upper end of said drive shaft and also connected to said outer case assembly, coupling means for coupling said hammer and said drive shaft for providing rotational and longitudinal movement of the hammer relative to said shaft and resilient means tending to resist longitudinal movement of said hammer and urge said clutch into engagement to connect said anvil with said hammer.

2. The apparatus in claim 1 in which said coupling means for coupling said hammer and said drive shaft comprises mated inclined channels in said hammer and said drive shaft and a bearing positioned in said channels.

3. An apparatus for drilling a borehole in the earth including a drill string and comprising an outer case assembly adapted to be attached at its upper end to said drill string, an anvil positioned in said outer case assembly with its upper surfaces having lugs thereon, means for rotatably and slideably supporting said anvil within said outer case assembly, a drill bit connected to said anvil, a hammer positioned above said anvil with its lower end having lugs similar to those on the upper end of said anvil, a drive shaft positioned adjacent said hammer, a prime mover coupled on the upper end of said drive shaft and connected to said outer case assembly, coupling means for coupling said hammer and said drive shaft for providing rotational and longitudinal movement of said hammer relative to said shaft, and resilient means surrounding said drive shaft and supported by said hammer for resisting longitudinal movement of said hammer and hold the lugs in engagement to connect said anvil with said hammer.

References Cited in the le of this patent UNITED STATES PATENTS 1,523,629 Bullock Jan. 20, 1925 1,607,082 Howcott Nov. 16, 1926 2,371,248 McNamara Mar. 13, 1945 2,641,445 Snyder June 9, 1953 2,750,154 Boice June 12, 1956 

1. AN APPARTUS FOR DRILLING A BOREHOLE IN THE EARTH INCLUDING A DRILL STRING AND COMPRISING AN OUTER CASE ASSEMBLY ADAPTED TO BE ATTACHED AT ITS UPPER END TO SAID DRILL STRING, AN ANVIL POSITIONED IN SAID OUTER CASE ASSEMBLY, MEANS FOR ROTATABLY AND SLIDEABLY SUPPORTING SAID ANVIL TO SAID OTER CASE ASSEMBLY, A DRILL BIT CONNECTED TO SAID ANVIL, A HAMMER POSITIONED ABOVE SAID ANVIL, A CLUTCH CONNECTING SAID ANVIL TO SAID HAMMER, A DRIVE SHAFT POSITIONED IN SAID HAMMER, A PRIME MOVER CONNECTED ON SAID OUTER CASE ASSEMBLY, COUPLING MEANS FOR COUPLING SAID HAMMER AND SAID DRIVE SHAFT FOR PROVIDING ROTATIONAL AND LONGITUDINAL MOVEMENT OF THE HAMMER RELATIVE TO SAID SHAFT AND RESILIENT MEANS TENDING TO RESIST LONGITUDINAL MOVEMENT OF SAID HAMMER AND URGE SAID CLUTCH INTO ENGAGEMENT TO CONNECT SAID ANVIL WITH SAID HAMMER. 